Laboratory Diagnosis of

Differential Characteristics of

Commonly Isolated Mycobacterium spp.

Mycobacterium

tuberculosis

Mycobacterium tuberculosis Infections

Incidence of Tuberculosis in USA

Mycobacterium

tuberculosis

Infections (cont.)

Positive PPD + Chest X-Ray +

MDR-TB a serious global health threat

BCG (bacille Calmette-Guerin)

= attenuated M. bovis

Typical Progression of

Pulmonary Tuberculosis

Pneumonia

Granuloma formation with fibrosis

Caseous necrosis

•Tissue becomes dry & amorphous (resembling cheese)

•Mixture of protein & fat (assimilated very slowly)

Calcification

•Ca++ salts deposited

Cavity formation

•Center liquefies & empties into bronchi

PPD Tuberculosis Skin Test Criteria

PPD = Purified Protein Derivative from M. tuberculosis

Chest X-Ray of Patient with Active Pulmonary Tuberculosis